In the past dumbbells have been provided which have been filled with a liquid such as water for the purpose of increasing the weight of the dumbbell such as U.S. Pat. No. 3,334,899 which provides for a hand-held dumbbell which is filled with water, etc., its principle purpose being to provide different sizes of dumbbells to be filled with varied amounts of liquid and is also concerned with transparency. The U.S. Pat. No. 4,854,576 also teaches a collapsible weight system involving a collapsible diaphragm to allow varied amounts of water to be sealed within it's structure to increase or decrease it's weight. U.S. Pat. No. 4,854,575 also teaches a fluid fillable, collapsible dumbell in a doughnut-shape.
The above patents teach water filled devices with their primary purpose being to use liquid and more particularly water as the weight medium, while the present invention is designed for a further purpose, that is, the control of the liquid as the device is moved out of it's horizontal plane which allows the liquid to flow from one chamber to another to create a progressive resistance, twisting principle of muscle development.